Characterization and classification of soils of Muger Sub-Watershed, Northern Oromia, Ethiopia

Abstract

Soil characterization and classification is the main information source for soil management and precision agriculture. However, much of Ethiopia’s documented soil information is scanty and inadequate relative to the large size of the country and the wide diversity of soils and landscapes. This study was, therefore, conducted with the objective of characterizing and classifying soils of the Muger sub-watershed in North Shoa Zone of Oromia Regional State, Ethiopia. Three slope classes were considered and eight representative pedons (P01-P08) were opened and described at the study area. Soil samples collected from identified horizons of each pedon were analyzed following standard procedures. The field as well as the laboratory data revealed that the textural classes of most of the pedons were sandy clay loam followed by sandy clay. The soils are acidic to neutral in reaction (pH 5.59-7.24). Organic carbon, cation exchange capacity, and percent base saturation of the soils range from 0.41 to 4.06%, 26.42 to 60.94 cmol (+)kg^-1 and 56.58 to 93.97%, respectively. The dominance of exchangeable bases was in the order of Ca²⁺>Mg²⁺>K⁺>Na⁺. The soils are low to high in available P and total N contents whilst varying from low to high in the contents of available micronutrients measured. The contents of soil organic carbon range from very low to high whereas the CEC and percent base saturation of the soils vary from medium to very high. It is concluded that the soils are classified as Mollic Leptosols (Eutric) (P01, P02, P05, P06 and P08), Pellic Vertisols (Grumic) (P04 and P07), and Rhodic Nitisols (Haplic) (P03) according to the World Reference Base for Soil Resources, and are dominantly sandy clay loam in texture varied contents of organic matter, available phosphorus, total nitrogen, and CEC. The wide variations in the pedons and physico-chemical properties of the soils imply designing land use system appropriate to specific needs of each soil class as well as implementing integrated soil fertility management practices to maintain soil organic matter and essential plant nutrients.

Keywords: Chemical Characteristics; Horizon; Morphological Characteristics; Physical Characteristics; Pedon; World Reference Base